2,4,7-TRISUBSTITUTED-{8 PYRIDO 2,3-d{9 PYRIMIDINE-6-CARBOXAMIDES

ABSTRACT

Novel 2,4,7-trisubstituted-pyrido(2,3-d)pyrimidine-6carboxamides have been produced which have central nervous system depressant activity and are useful pharmacological agents in the calming of animals.

United States Patent 1 Santilli et al.

[ 1 3,725,405 51 Apr. 3, 1973 [54] 2,4,7-TRISUBSTITUTED-[PYRIDO 2,3-

D]PYRIMIDINE-6-CARBOXAMIDES [75] Inventors: Arthur A. Santilli, Havertown; Dong H. Kim, Wayne, both of Pa.

[73] Assignee: American Home Products Corporation, New York, N.Y.

[22] Filed: June 18, 1970 [21] Appl. No.: 47,571

[52] US. Cl....260/247.2 A, 260/247.l, 260/2564 F, 260/256.4 N, 260/2565 R, 424/248,

[51] Int. Cl. ..C07d 57/20 [58] Field of Search...260/256.4 F, 256.5 R, 247.2 A. 260/247.1

[56] References Cited UNITED STATES PATENTS 2/l962 Hitchings et al. ..260/256.4 F

4/1966 Ohnacker ..260/256.4F 2/1967 Ohnacker ..260/256.4F

[57] ABSTRACT Novel 2,4,7-trisubstituted-pyrido[2,3-dlpyrimidine-6- carboxamides have been produced which have central nervous system depressant activity and are useful pharmacological agents in the calming of animals.

7 Claims, No Drawings 2 ,4,7-TRlSUBSTITUTED-[PYRIDO 2,3- D]PYRl1VIIDlNE6-CARBOXAMIDES DESCRIPTION OF TI-lE INVENTION The invention is concerned with compounds of FOR- MULA I NHz wherein R is selected from the group consisting of phenyl, halophenyl, (lower)alkoxyphenyl, (lower)alkylphenyl and (lower)alkylthio; R is selected from the group consisting of (lower)alkoxyethyl, hydroxy(lower)alkyl, (lower)alkoxycarbonyl-methyl, phenethyl, halophenethyl, (lower)alkoxyphenethyl, (lower )alkylphenethyl, and

mun. N

N Il -KN wherein R, is the same as hereinabove described.

When used herein and in the appended claims, the term (lower)alkyl contemplates hydrocarbon radicals, straight and branched, of from one to six carbon atoms; illustrative members of the group being methyl, ethyl, n-propyl, i-propyl, n-butyl; t-butyl, n-pentyl, nhexyl and the like. The term (lower)alkoxy contemplates hydrocarbonoxy groups of from one to six carbon atoms, straight chain and branched, and includes methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, n-pentoxy, n-hexyloxy and the like. The compounds of FORMULA ll may be prepared by treating the appropriate 4,6-dichloro, 2-substituted pyrimidine with concentrated ammonium hydroxide solution in the presence of a lower alkanol such as methanol, ethanol or propanol. The reaction mixture is heated for about l hour and then cooled. To prepare compounds of FORMULA l, the recrystallized product thus obtained is combined in ethanolic sodiumethoxide which has been prepared by the addition of sodium metal to an excess of ethanol. Then the appropriate 2-cyano N- substituted acetamide or N,N'-bis(substituted) malonarnide is added and the reaction mixture is refluxed and the 2,4,7-trisubstituted-pyrido[2,3-d] pyn'midine-6-carboxamides are then recovered from the reaction mixture.

Two methods are useful for the isolation of the products from the reaction mixture. It may be possible to separate the product by filtering the precipitate that readily forms in the heated reaction mixture. As an alternative method it may be necessary to cool the reaction mixture in ice to separatethe product as a crystalline precipitate. The product may then be purified by recrystallization from ethanol, aqueous dimethylforrnamide etc.

The starting materials for the preparation of FOR- MULA II are commercially available or may be prepared by techniques well-known to those skilled in the art.

' In the pharmacological evaluation of the biological activity of the compounds of this invention, the in vivo effects were tested as follows:

The compound was administered orally or intraperitoneally to three mice (14 to 24 grams) at each of the following doses: 400, 127, 40 and 12.7 milligrams per kilogram of host body weight (MPK). The animals were watched for a minimum of two hours during which time signs of general stimulation, (i.e., increased spontaneous motor activity, hyperactivity on tactile stimulation, twitching), general depression (i.e., decreased spontaneous motor activity, decreased respiration), autonomic activity (i.e., miosis, mydriasis, diarrhea) were noted. The compounds of this invention induce central nervous system depressant effects at a dose of 127 to 400 MPK. Thus, the compounds of the invention have demonstrated utility as pharmacologically active compounds in experimental and comparative pharmacology and are of value in the treatmentof mammals, e.g. mice, rats, etc., who are responsive to treatment with central nervous system depressant agents. Specifically the compounds may be administered for the purpose of inducing a calming effect in mammals.

When the compounds of this invention are employed as described above, they may be administered alone or in combination with pharmacologically acceptable carriers, the proportion of which is determined by the solubility and chemical nature of the compound, chosen route of administration and standard pharmacological practice. For example, they may be administered orally in the form of tablets or capsules containing such excipients as starch, milk, sugar, calcium carbonate and the like. They may be administered orally in the form of solutions which may contain coloring and flavoring agents or they may be administered by parenteral injection, e.g., intramuscular injection. The injectionable solution may contain other solutes such as sodium chloride or glucose in a sufficient quantity to render the solution isotonic.

The dosage of the pharmacological therapeutic agents of the invention will vary with the route of administration and the particular compound chosen. Furthermore, it will vary with the particular subject under treatment. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the compound. Thereafter, the dosage may be increased by small increments until the optimum effect under the circumstances is reached.

While the invention has been described in its broadest form hereinabove, the following examples are added to set forth specific embodiments of the methods of preparing the compounds of the invention.

EXAMPLE 1 4,6-Diamino-2-phenyl-5-pyrimidinecarboxaldehyde To 50 ml. of concentrated ammonium hydroxide solution in a pressure flask is added 15 g. of 4,6- dichloro-2-phenyl-5-pyrimidinecarboxaldehyde. The mixture is heated on a steam bath for 1 hour and a suffi cient quantity of ethanol is added to solubilize the mixture. Heating is continued for an additional hour. The reaction is cooled in ice and the crystalline product that is deposited (9.5 g.) is recrystallized from ethanol. The product has a m.p. of 217-218C.

AnaLCalcd for C H N O: C, 61.67; H, 4.71; N,

26. l 6. Found: C, 61.50; H, 4.40; N, 26.13.

EXAMPLE ll 4,6-Diamino-2-methylthio-5-pyrimidinecarboxaldehyde is prepared as in Example I from 15 g. of 4,6- dichloro-2-methylthio-5-pyrimidinecarboxaldehyde in 80 ml. of concentrated ammonium hydroxide. The product amounts to g. Recrystallization from ethanol yields an analytical sample, m.p. 228230C.

Anal. Calcd for C H N OS: C, 39.12; H, 4.37; N,

30.41; S, 17.40. Found: C, 39.08; H, 4.38; N, 30.06; S, 17.15.

EXAMPLE III 4,7-Diamino-N-cyc1ohexyl-2-(methylthio)pyrido[2,3- d ]pyrimidine-6-carboxamide To a solution of 0.23 g. of sodium metal in ethanol is added 1.84 g. of 4,6-diamino-2-methylthio-5- pyrimidinecarboxaldehyde and 1.6 g. of 2-cyano-N- cyclohexyl acetamide. The reaction mixture is heated with stirring under reflux for 30 minutes during which time a yellow crystalline product is deposited. Recrystallization from aqueous dimethylformamide yields 0.5 g. of product, m.p. 360.

Anal. Calcd for G i-1 N 05: C, 54.36; H, 5.78; N,

25.36; S, 9.67. Found: C, 54.07; H, 6.04; N, 24.97; S, 9.36.

EXAMPLE IV 4,7-Diamino-N-( 2-dimethylaminoethyl)-2- (methylthio )pyrido [2,3-d ]-pyrimidine-6-carboxamide To a solution of 0.23 g. of sodium in absolute ethanol is added 1.2 g. of 4,6-diamino-2-methylthio-5- pyrimidinecarboxaldehyde and 1.1 g. of 2-cyano-N-( 2- dimethylaminoethyl)acetamide. The reaction mixture is heated under reflux for 2 hours and allowed to stand overnight in the refrigerator. A yellow crystalline product is deposited. Recrystallization from ethanol yields 0.3 g. of product, m.p. 297300C.

Anal. Calcd for C H N OS: C, 48.58; H, 5.96; N,

30.51; S, 9.97. Found: C, 48.52; H, 5.85; N, 30.45; S, 9.99.

EXAMPLE V 4,7-Diamino-N-(2-methoxyethyl)-2-phenylpyrido[.2,3- d]pyrimidine -6-ca.rboxa.mide

To 0.69 g. of sodium in ml. of ethanol is added 6.12 g. of 4,6-diamino-2-phenyl-5-pyrimidinecarboxaldehyde and 4.26 g. of 2-cyano-N-(2-methoxyethyl)acetamide. The reaction mixture is heated under reflux with stirring for one hour. After cooling in ice a precipitate is deposited. Recrystallization from ethanol yields 1.0 g. of product, m.p. 25 8-26 1C.

Anal. Calcd for C H N O C, 60.34; H, 5.36; N,

24.84. Found: C, 60.08; H, 5.26; N, 24.90.

EXAMPLE VI EXAMPLE VII 4-amino-7-hydroxy-N-(2-methoxyethyl)-2-phenylpyrido[2,3-dl-pyrimidine-6-carboxamide To a solution containing 0.69 g. of sodium in 60 ml. of absolute ethanol is added 6.1 g. of 4,6-diamino-2- phenyl-Spyrimidinecarboxaldehyde and 5.9 g. of N,N'-

bis(2-methoxy-ethyl)malonamide. The reaction mix ture is heated under reflux with stirring for 3 hours and then cooled in ice. The yellow precipitate which is deposited is collected on a filter and recrystallized from aqueous dimethylformamide. The product amounts to 2 g., m.p. 360.

Anal. Calcd for C H N O C, 60.17; H, 5.05; N,

20.64. Found: C, 59.60; H, 4.94; N, 20.79. 7

EXAMPLE VIII By methods analogous to those employed above, the following compounds are prepared:

1. A compound selected from the group consisting of:

' i fH wherein R is selected from the group consisting of cyclohexyl phenyl, halophenyl, (lower)alkoxyphenyl, (lower)a1kylphenyl and (lower)a1kylthio; R is selected from the group consisting of cyclohexyl, (lower)alkoxyethyl, hydroxy(lower)alkyl, (lower)a.lkoxycarbonylmethyl, phenethyl, halophenethyl, (lower)alkoxyphenethyl, (lower)alkylphenethyl, and

. N/ tCHQ) R4 wherein R and R when not concatenated are independently selected from the group consisting of hydrogen, (lower)alkyl and (lower)alkoxy; when R and R are concatenated they form a radical selected from the nyl and pyrrolidinyl; n is an integer of from 1 to 4; R 'is selected from the group consisting of hydroxy and amino.

2. A compound as defined in claim 1 wherein R is phenyl or (lower) alkylthio; R is cyclohexyl; (lower)alkoxy-ethyl, di(lower)a1kylaminoethyl, or morpholino;

' diamino-N-( Z-methoxyethyl)-2phenylpyrido[ 2,3-d 1 pyrimidine -6-carboxamide.

6. A compound as described in claim 2 which in: 4,7- diamino-N-( Lmorpholinoethyl )-2-phenylpyridol 2 ,3 d]pyrimidine -6'carboxamide.

7. A compound as described in claim 2 which is: 4- amino-7-hydroxy-N-(2-methoxyethyl)-2-phenylpyrido[2,3-d]-pyrimidine-6-carboxamide. 

2. A compound as defined in claim 1 wherein R1 is phenyl or (lower) alkylthio; R2 is cyclohexyl; (lower)alkoxy-ethyl, di(lower)alkylaminoethyl, or morpholino; and R5 is hydroxy or amino.
 3. A compound as described in claim 2 which is: 4,7-diamino-N-cyclohexyl-2-(methylthio)pyrido(2,3-d)pyrimidine -6-carboxamide.
 4. A compound as described in claim 2 which is: 4,7-diamino-N-(2-dimethylaminoethyl)-2-(methylthio)pyrido(2,3-d)-pyrimidine -6carboxamide.
 5. A compound as described in claim 2 which is: 4,7-diamino-N-(2-methoxyethyl)-2-phenylpyrido(2,3-d)pyrimidine -6-carboxamide.
 6. A compound as described in claim 2 which is: 4,7-diamino-N-(2-morpholinoethyl)-2-phenylpyrido(2,3-d)pyrimidine -6-carboxamide.
 7. A compound as described in claim 2 which is: 4-amino-7-hydroxy-N-(2-methoxyethyl)-2-phenylpyrido(2,3-d)-pyrimidine-6 -carboxamide. 